1. Field of the Invention
The present invention generally relates to hydraulic pruning shears or secateurs having a contained controlling device and more specifically to such apparatus as particularly used for cutting or harvesting in arboriculture, viticulture and horticulture.
2. Description of Prior Art
Hydraulic secateurs or pruning/cutting shears are known which comprise a blade or hook rigidly attached to and integral with the front portion of a body serving as a handle, a pivotable blade journalled on the hook and connected, by means of a connecting rod, to the shaft of a piston moving in sliding and sealed fashion within a bore of the body, and a hydraulic distributor generally activated by a lever or trigger and adapted to control the movements of the piston to assure the closing and opening of the blade.
According to the known embodiments of hydraulic pruning shears or secateurs of this type, it is not possible to synchronize the speed and amplitude of the pivoting movements of the mobile blade with the speed and amplitude of the trigger's movements; accordingly, the activation or release of the trigger unavoidably causes the substantially complete closing or opening of the blade, in sudden fashion, depending upon the power of the tool. This constitutes a source of danger, because it is practically impossible to stop the flapping of the mobile blade in the direction of the fixed blade when the hydraulic distributor has been activated. This is also a notable disadvantage, because it is often desirable to reduce the spacing of the blade for penetrating into relatively dense vegetation, so as to limit the chance that the device will get caught upon other objects in its path.